Enhancing oral bioavailability of andrographolide via sodium dodecyl sulfate and D-α-Tocopherol polyethylene glycol 1000 succinate copolymer modified nanocrystals
Nanocrystal technology is a common strategy to enhance the oral bioavailability of poorly-soluble drugs, and how to enlarge the enhancing ability on oral absorption via nanocrystals has become a pharmaceutical research field. In this study, we selected andrographolide (ADR), a typical poorly-soluble drug, as the model drug, and employed sodium dodecyl sulfate and D-ɑ-Tocopherol polyethylene glycol 1000 succinate copolymer (SDS-TPGS) to construct novel SDS-TPGS modified andrographolide nanocrystals (S-TANs). We found that the particle sizes of SDS/TPGS physical mixture modified nanocrystals (STANs) were about 553.4 ± 4.1 nm , while that of SDS-TPGS modified nanocrystals (S-TANs) were 604.6 ± 5.7 nm. During the production process of nanocrystals, the crystallinity of ADR was slightly decreased. Nanocrystals enhanced the saturation solubility of ADR, and improved oral absorption, C max and AUC 0-∞ of S-TANs was about 2.10 and 1.24 fold increased, STAN about 2.63, 2.97 fold. In a Real-time distribution study, we found the distribution time of andrographolide, SDS and TPGS in SDS/TPGS physical mixture modified nanocrystals system varies widely, while the distribution times of these materials were similar in SDS-TPGS copolymer modified nanocrystals system. These results indicated that modified with functional stabilizer was an efficient strategy to enlarge the enhancing ability on oral absorption of nanocrystals, and synthesized copolymer containing different functional stabilizers showed higher ability on enhancing oral bioavailability than physical mixtures.
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